do not report use-before-declaration error in async IIFE initializer

src/compiler/checker.ts

@@ -2632,7 +2632,7 @@ namespace ts {
          */
         function isSameScopeDescendentOf(initial: Node, parent: Node | undefined, stopAt: Node): boolean {
             return !!parent && !!findAncestor(initial, n => n === parent
-                || (n === stopAt || isFunctionLike(n) && !getImmediatelyInvokedFunctionExpression(n) ? "quit" : false));
+                || (n === stopAt || isFunctionLike(n) && (!getImmediatelyInvokedFunctionExpression(n) || isAsyncFunction(n)) ? "quit" : false));
         }
 
         function getAnyImportSyntax(node: Node): AnyImportSyntax | undefined {

tests/baselines/reference/blockScopedVariablesUseBeforeDef.errors.txt

@@ -152,4 +152,16 @@ tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts(122,22): error TS2448:
 !!! error TS2448: Block-scoped variable 'a' used before its declaration.
 !!! related TS2728 tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts:122:10: 'a' is declared here.
     }
+
+    function foo17() {
+        const promise = (async () => {
+            promise
+            foo
+            await null
+            promise
+            foo
+        })()
+
+        const foo = 1;
+    }
 

tests/baselines/reference/blockScopedVariablesUseBeforeDef.js

@@ -122,9 +122,57 @@ function foo15() {
 function foo16() {
     let [a] = (() => a)();
 }
+
+function foo17() {
+    const promise = (async () => {
+        promise
+        foo
+        await null
+        promise
+        foo
+    })()
+
+    const foo = 1;
+}
 
 
 //// [blockScopedVariablesUseBeforeDef.js]
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+var __generator = (this && this.__generator) || function (thisArg, body) {
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
+    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    function verb(n) { return function (v) { return step([n, v]); }; }
+    function step(op) {
+        if (f) throw new TypeError("Generator is already executing.");
+        while (_) try {
+            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
+            if (y = 0, t) op = [op[0] & 2, t.value];
+            switch (op[0]) {
+                case 0: case 1: t = op; break;
+                case 4: _.label++; return { value: op[1], done: false };
+                case 5: _.label++; y = op[1]; op = [0]; continue;
+                case 7: op = _.ops.pop(); _.trys.pop(); continue;
+                default:
+                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
+                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
+                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
+                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
+                    if (t[2]) _.ops.pop();
+                    _.trys.pop(); continue;
+            }
+            op = body.call(thisArg, _);
+        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
+        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
+    }
+};
 function foo0() {
     var a = x;
     var x;
@@ -254,3 +302,22 @@ function foo15() {
 function foo16() {
     var a = (function () { return a; })()[0];
 }
+function foo17() {
+    var _this = this;
+    var promise = (function () { return __awaiter(_this, void 0, void 0, function () {
+        return __generator(this, function (_a) {
+            switch (_a.label) {
+                case 0:
+                    promise;
+                    foo;
+                    return [4 /*yield*/, null];
+                case 1:
+                    _a.sent();
+                    promise;
+                    foo;
+                    return [2 /*return*/];
+            }
+        });
+    }); })();
+    var foo = 1;
+}

tests/baselines/reference/blockScopedVariablesUseBeforeDef.symbols

@@ -256,3 +256,28 @@ function foo16() {
 >a : Symbol(a, Decl(blockScopedVariablesUseBeforeDef.ts, 121, 9))
 }
 
+function foo17() {
+>foo17 : Symbol(foo17, Decl(blockScopedVariablesUseBeforeDef.ts, 122, 1))
+
+    const promise = (async () => {
+>promise : Symbol(promise, Decl(blockScopedVariablesUseBeforeDef.ts, 125, 9))
+
+        promise
+>promise : Symbol(promise, Decl(blockScopedVariablesUseBeforeDef.ts, 125, 9))
+
+        foo
+>foo : Symbol(foo, Decl(blockScopedVariablesUseBeforeDef.ts, 133, 9))
+
+        await null
+        promise
+>promise : Symbol(promise, Decl(blockScopedVariablesUseBeforeDef.ts, 125, 9))
+
+        foo
+>foo : Symbol(foo, Decl(blockScopedVariablesUseBeforeDef.ts, 133, 9))
+
+    })()
+
+    const foo = 1;
+>foo : Symbol(foo, Decl(blockScopedVariablesUseBeforeDef.ts, 133, 9))
+}
+

tests/baselines/reference/blockScopedVariablesUseBeforeDef.types

@@ -287,3 +287,35 @@ function foo16() {
 >a : any
 }
 
+function foo17() {
+>foo17 : () => void
+
+    const promise = (async () => {
+>promise : Promise<void>
+>(async () => {        promise        foo        await null        promise        foo    })() : Promise<void>
+>(async () => {        promise        foo        await null        promise        foo    }) : () => Promise<void>
+>async () => {        promise        foo        await null        promise        foo    } : () => Promise<void>
+
+        promise
+>promise : Promise<void>
+
+        foo
+>foo : 1
+
+        await null
+>await null : null
+>null : null
+
+        promise
+>promise : Promise<void>
+
+        foo
+>foo : 1
+
+    })()
+
+    const foo = 1;
+>foo : 1
+>1 : 1
+}
+

tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts

@@ -1,4 +1,5 @@
 // @target: ES5
+// @lib: esnext, dom
 function foo0() {
     let a = x;
     let x;
@@ -122,3 +123,15 @@ function foo15() {
 function foo16() {
     let [a] = (() => a)();
 }
+
+function foo17() {
+    const promise = (async () => {
+        promise
+        foo
+        await null
+        promise
+        foo
+    })()
+
+    const foo = 1;
+}